Apparatus for treatment of rubber and plastic wastes

ABSTRACT

An apparatus for treatment of rubber and plastic wastes, comprising in series an extruder for heating and melting rubber and plastic wastes to extrude the molten wastes, a decomposing section for heating the molten wastes to prepare decomposed products while optionally separating residues therefrom, a dry-distilling section for gasifying the decomposed products by dry-distillation, and a cooling section for cooling the dry-distilled products to separate gaseous materials from liquid materials.

This is a division of application Ser. No. 512,799, filed Oct. 4, 1974now U.S. Pat. No. 3,984,288.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to a method for treatment of rubber and plasticwastes and apparatus therefor, and in particular, to a method forliquefying the wastes by pyrolysis and apparatus therefor.

2. Description of the Prior Art

Two conventional liquefying processes are known for treatment of rubberand plastic wastes. One process comprises heating and melting the rubberand plastics, feeding the molten substances to a pyrolysis reactionfurnace and decomposing and dry-distilling the molten substances at thesame time in the reaction furnace to liquefy the decomposed products.The other process comprises feeding the plastics directly to a pyrolysisreaction furnace and heating and melting the plastics therein using aheat transfer duct or the like with a simultaneous decomposition anddry-distillation thereof employing the molten substances as a heattransfer medium thereby to liquefy the decomposed products. In theseconventional processes, the temperature in the heating means is almostuniform as a whole including the decomposing means and thedry-distilling means. This is, however, somewhat defective for thefollowing reasons. If the temperature is to be elevated in order toaccelerate the decomposition speed, the temperature must be elevated inall of the pyrolyzing means. However, rubber and plastics themselveshave poor thermal conductivity, and therefore it is difficult to elevatethe temperature in the pyrolyzing means easily. Accordingly, a specificheater which can elevate the temperature in the pyrolysis means muchhigher than is required or a lot of heaters must be used therefor.Various trials have heretofore been effected in an effort to acceleratethe decomposition speed and to improve the decomposition efficiency, butno effective means have as yet been found. Accordingly, generally in theconventional processes, the pyrolysis is carried out for a long periodof time at a temperature of 400° to 500° C. In order to treat a largeamount of wastes, pyrolysis of the wastes for a long period of time inan apparatus provided with a large-sized decomposing trough has beensuggested.

Moreover, conventional processes are further defective in that thepyrolyzed products are not uniform, and oils having quite differentproperties are recovered and obtained. The properties of the recoveredoils vary widely in the treatment of any rubber and plastic materials,and the recovered oils comprise various kinds of components of anextensively broad range of from a light fraction having a fairly lowflash point to waxes having a high pour point.

SUMMARY OF THE INVENTION

An object of this invention is to obtain recovered oils having uniformproperties in the treatment of rubber and plastic wastes.

Accordingly, this invention provides a method for continuouslypyrolyzing and liquefying rubber and plastic wastes and an apparatustherefor where the decomposition speed and the decomposition efficiencyare accelerated and improved using three separate means of a heating andmelting means, a decomposing means and a dry-distilling means. In themethod and apparatus of this invention, an extruder is used as theheating and melting means, the decomposing means includes a heating andmelting means and a decomposing duct in which the temperature is higherthan that in the dry-distilling means, and the dry-distilling meansincludes a dry-distilling trough, and the melting means, decomposingmeans and dry-distilling means are disposed in series for continuousoperation and are so constructed that the temperature of the respectivemeans can be controlled individually.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS

FIGS. 1 to 6 are schematic views of the embodiments of the apparatusaccording to the present invention.

DETAILED DESCRIPTION OF THE INVENTION

This invention is explained in detail hereinafter with reference todrawings attached hereto.

In FIG. 1, element 1 is an extruder where rubber and plastic wastes arekneaded and melted to continuously extrude the molten substances into aheating and decomposing duct 2. In the duct 2, the heating temperatureis controlled by heat control unit 22 actuating heating element 20 at atemperature higher than the temperature in the extruder 1 anddry-distilling trough 3. The trough 3 is connected with the duct 2, andthe decomposed products are fed into the trough 3 through the duct 2,and then the decomposed products are successively gasified bydry-distillation in the trough 3. Element 4 is a heater for heating thedecomposing duct controlled by heat controller 24. As shown 5 is aheater for heating the dry-distilling trough controlled by heat controlunit 26. Various means can be utilized for heating the extruder,decomposing duct and dry-distilling trough, such as a band-heater, acast heater, a high frequency induction heating means, an oil heatingmeans, a steam heating means, a hot-air heating means and a gas heatingmeans. The means for heating the extruder, decomposing duct anddry-distilling trough are appropriately selected, depending upon thekinds of rubber and plastic wastes to be treated or the temperature inthese means to be heated. A band-heater, cast heater, gas heating meansand hot-air heating means are preferred for heating the decomposingduct, and an oil heating means, steam heating means and hot-air heatingmeans are preferred for heating the dry-distilling trough.

These means are so constructed that the temperature of each means can becontrolled individually. The individual controlling means are differentin accordance with the heating means employed. Outlets 6 for removingthe decomposed residues and 7 for expelling gaseous products afterdry-distillation are shown in the Figures.

The dry-distilled gaseous products removed from the dry-distillingtrough 3 are cooled to ambient temperature, by passage through aconventional cooling trough 8 or a condenser, whereby liquid productsand products gaseous at ambient temperature are separated from eachother, and then the liquid products are retained in an oil tank 9. Thegaseous products are introduced into a gas holder, passing through anoutlet 10 for removing the gaseous products.

If the gaseous products contain hydrogen chloride gas from thedecomposition of, e.g., vinyl chloride, etc., the gaseous productspreferably are introduced into a known absorbing tower to absorb thehydrogen chloride therein. Afterwards, the small amount of residualhydrochloric acid formed in the absorption is neutralized with an alkaliin an neutralizing tower or the like, and then only a pure hydrocarbongas is placed in the gas holder. The gaseous products can be used as aheat source for the decomposition, and these are released into the airafter perfect combustion. In addition, when liquid products having moreuniform properties are to be obtained, the gaseous products areintroduced to a fractionating tower or the like from the outlet 7 tofractionate them into uniform components.

The extruder 1 used in this invention can be any conventional extruderfor rubber and plastics. For example, a single spindle screw-typeextruder, a double spindle screw-type extruder, a single spindletwo-stage screw-type extruder, and a double spindle two-stage screw-typeextruder can be employed.

The rubber and plastic waste raw materials are fed into the extruder 1,and the waste materials can be pre-worked prior to the feeding thereofinto the extruder 1, to pulverize the materials to almost the same sizes(about 5 to 10 mm). Some waste materials are pre-heated and then fedinto the extruder in a semi-molten state. Other waste materials are fedinto the extruder in a block or sheet form.

The temperature in the extruder is varied depending upon the rawmaterials fed into the extruder, but it is necessary to elevate thetemperature in the extruder so that the materials can fully be kneadedand melted and to keep the temperature so that the molten materialsremain melted.

The temperature in the heating and decomposing duct 2 is controlled byheat control unit 22 to a temperature higher than the temperature inboth of the extruder and the dry-distilling trough, and the temperatureis varied depending upon the raw materials sent from the extruder. Ifthe temperature in the heating and decomposing duct is lower than thetemperature in the extruder and the dry-distilling trough, it isimpossible to obtain liquid products having uniform properties, as shownin the following Comparative Examples. In addition, the temperature inthe heating and decomposing duct also is varied by heat control unit 24actuating on heating means 4 depending upon the amount of materials sentfrom the extruder. In any event, it is necessary to elevate thetemperature in the heating and decomposing duct so that the moltenresins can be decomposed at a sufficient rate and to maintain thetemperature as such for a sufficient period of time until thedecomposition of the molten resins is completed.

The temperature in the dry-distilling trough is elevated so that thedecomposed products can be dry-distilled and gasified completely.

The continuous heating and decomposing treatment preferably is carriedout at temperatures each falling within the following ranges:

    ______________________________________                                        Temperature in the extruder:                                                                       lower than about 100° to                                               400° C.                                           Temperature in the decomposing                                                duct:                about 400° C. or                                                       more to 1000° C.                                  Temperature in the dry-distilling                                             trough:              lower than                                                                    about 100° to 400° C.                      ______________________________________                                    

According to the present invention, it is possible to liquefy variouskinds of rubber and plastic composition wastes, for example, as follows:

Polyolefin resin compositions and crosslinked products thereof, such aslow density polyethylene, high density polyethylene, polypropylene,ethylene-vinyl acetate copolymers, ethylene-ethyl acrylate copolymers,polybutene and ethylenebutene copolymers; polystyrene resin compositionssuch as polystyrene, styrene-acrylonitrile copolymers andacrylonitrile-butadiene-styrene copolymers (ABS resin); vinyl andvinylidene resin compositions such as polyvinyl chloride, polyvinylalcohol, polyvinyl acetate, vinyl chloride-vinyl acetate copolymers, andpolyethylene-vinyl acetate copolymers; polyacrylic resin compositionssuch as polymethylacrylate and polymethylmethacrylate polyamide resincompositions such as nylon 6, nylon 66 and nylon 610 copolymers, rubbercompositions such as natural rubber, butadiene rubber, butyl rubber,isoprene rubber, styrene-butadiene rubber and ethylene-propylene rubber.

In order to effectively carry out the method of this invention toimprove the decomposition efficiency and to increase the amount ofmiddle component obtainable from decomposed products, it is advantageousto feed an active gas into the above decomposing means, which is anotherembodiment of this invention.

With reference to FIG. 2, the heating and decomposing duct 4 includes aninlet 11 for feeding an active gas, and an active gas capable of easilyreacting with the olefins of the rubber and plastic decomposed products,such as oxygen, hydrogen, ozone or air, is fed from the inlet 11. Theamount of the active gas fed is varied depending upon the kinds ofrubber and plastic compositions decomposed and the amount ofcompositions sent from the extruder to the heating and decomposing duct.

By carrying out the heating and decomposition of waste materials whilefeeding an active gas into the decomposing means, it is possible toobtain recovered oils with more uniform properties and to reduce thecontent of the olefins in the fractions obtained thereby to deodorizethe fractions.

Some deposits often remain in the heating and decomposing duct 2 and thedry-distilling trough 3 as the treatment of wastes according to themethod of this invention progresses, and it is advantageous to removethese deposits to improve the decomposition efficiency. This inventionalso includes still another embodiment where the deposits or residuesare removed from the heating and decomposing duct 2.

When polyethylene wastes are treated according to the present invention,some wastes include about 3% or so of carbon, and the carbon is ingeneral deposited in the dry-distilling trough.

When the wastes treated are crosslinked polyethylene, polystyrene andethylene-vinyl acetate copolymers, a metal oxide such as aluminum oxideor silicon oxide is admixed the wastes in an appropriate proportion ofabout 1 to 200 parts per 100 parts by weight of the wastes for thepurpose of accelerating the decomposition of the wastes anddeodorization, and in this case, a large amount of residues mainly ofthe metal oxide used is deposited in the dry-distilling trough. When theresidues of carbon or metal oxides deposited in the dry-distillingtrough are removed therefrom, decomposed products are also removedtogether with the residues, causing a deterioration of the decompositionefficiency.

This invention is free from this defect, and the decomposition rate andthe decomposition efficiency can be accelerated and improved, andrecovered oils with uniform properties can be obtained.

More precisely, this invention further provides an improved method fortreatment of rubber and plastic wastes and an apparatus therefor,comprising

(1) heating and melting rubber and plastic wastes at a temperature (T₁)to extrude the molten wastes with an extruder to a decomposing means,

(2) heating the molten wastes in the decomposing means at a highertemperature (T₂) than the heating temperature (T₁) in the extruder toseparate decomposed products and residues from each other,

(3) introducing the decomposed products into a dry-distilling meanswhile heating the residues in a residue removal means at an even highertemperature (T₃) than the heating temperature (T₂) in the decomposingmeans to remove the residues from the residue removal means,

(4) heating the decomposed product in the dry-distilling means at alower temperature (T₄) than the heating temperature (T₂) in thedecomposing means to gasify the products by dry-distillation, and

(5) cooling the dry-distilled products in a cooling means to separatethe liquid materials from the gaseous products.

This embodiment of the present invention will be explained in detailwith reference to drawings attached hereto.

In FIG. 3 element, 1 is an extruder where rubber and plastic wastes arekneaded and melted and the molten wastes are continuously successivelyextruded into a heating and decomposing duct 2. The heating temperature(T₂) in the duct 2 is controlled to a temperature higher than theheating temperature (T₁) in the extruder and the heating temperature(T₄) in the dry-distilling trough 3.

The dry-distilling trough 3 is connected with the duct 2, duct 13 is anoutlet for removing residues, and this outlet is branched in thevicinity of the outlet of the duct 2 and is connected with an extruder12. In the following Examples, this outlet 13 is provided facingdownward. For example, when the residues are metal oxides which areintermixed in a large amount, these are introduced into the extruder 12by a weir 16 and fall due to gravity, and the decomposed products whichwere substantially separated in the heating and decomposing duct 2 aremostly gasified and introduced into the dry-distilling trough 3. Sincethe heating temperature (T₃) in the residue removal means 13 and theextruder 12 is controlled to a temperature higher than the heatingtemperature (T₂) in the heating and decomposing duct 2, decomposedproducts contained in the residue which are still not separated aregasified in the extruder 12 and introduced into the dry-distillingtrough 3 via a duct 14 provided with a band-heater 15. Thus, onlyresidues which are substantially free from decomposed products arecontinuously exhausted to the outside by the extruder 12. In thefollowing Examples, the residues are transferred to the driving sidefrom the top end of the extruder 12. The extruder can be a simpleextruder. Some wastes contain a small amount of residues, and when theamount of residues is small, a pole bulb or a gate bulb can be used inplace of the extruder 12 to intermittently exhaust the residue.

The temperature in the extruder is varied depending upon the rawmaterials fed thereinto, but it is necessary to elevate the temperaturetherein so that the materials can fully be kneaded and melted and tomaintain the temperature so that the molten materials remain melted.

The temperature in the heating and decomposing duct 2 is controlled to atemperature higher than the temperature in both the extruder and thedry-distilling trough, and this is varied depending upon the rawmaterials sent from the extruder. If the temperature in the heating anddecomposing duct is lower than the temperature in the extruder and thedry-distilling trough, it is impossible to obtain liquid products havinguniform properties. In addition, the temperature in the heating anddecomposing duct also is varied depending upon the amount of materialssent from the extruder. In any event, it is necessary to elevate thetemperature in the heating and decomposing duct so that the moltenresins can be decomposed at a sufficient rate and to keep thetemperature as such for a sufficient period of time until thedecomposition of the molten resins is completed. The heating temperature(T₃) in the residue removal outlet 13 and the extruder 12 is controlledto a temperature higher than the heating temperature (T₂) in the heatingand decomposing duct 2 whereby the decomposed products contained inresidues still not yet separated therefrom are sent to thedry-distilling trough 3. Thus, the efficiency for separation is improvedfurther.

The temperature in the dry-distilling trough is elevated so that thedecomposed products can be completely dry-distilled and gasified.

It is preferred to carry out the continuous heating and decomposingtreatment at temperatures each falling within the following ranges:

    ______________________________________                                        Temperature (T.sub.1) in extruder 1 =                                                              lower than about 100°                                                  to 400° C.                                        Temperature (T.sub.2) in decomposing                                          duct 2 =             about 400° C.                                                          or more to 1000° C.                               Temperature (T.sub.3) in residue removal                                      outlet 13 and extruder 12 =                                                                        about 450° C. or more                                                  to 1000° C.                                       Temperature (T.sub.4) in dry-distilling                                       trough 3 =           lower than 100°                                                        to 400° C.                                        ______________________________________                                    

Still another embodiment of this invention is shown in FIGS. 4, 5 and 6,where a plurality of combined means, each comprising an extruder 1 and aheating and decomposing duct 2 which are directly connected in serieswith each other, are connected with one dry-distilling trough 3.

Various kinds of rubber and plastic wastes each having a differentmelting temperature and a different heating decomposing temperatureexist. Therefore, when a mixture of a number of different kinds ofrubber and plastic wastes are heated and decomposed at the same time, itis impossible to obtain liquid products having uniform properties. Thisinvention has solved this problem. More precisely, according to thelast-described embodiment of this invention, a number of different kindsof rubber and plastic wastes are separated individually, and therespective rubber and plastic wastes which have different meltingtemperatures and decomposing temperatures are separately treated in therespective combined means where the melting temperature and thedecomposing temperature are appropriately controlled in accordance withthe properties of the respective rubber and plastic wastes, to form anumber of different decomposed products, all of which products arethereafter introduced into one dry-distilling trough where all of thedecomposed products are dry-distilled at the same time. Thus, liquidmaterials having uniform properties can be effectively and efficientlyobtained.

Furthermore, it is effective to add at least one organic perioxide tothe rubber and plastic wastes to be treated, which is still anotherembodiment of this invention. By the addition of the organic peroxides,it is possible to accelerate the decomposition rate and to improve thedecomposition efficiency and the properties of the recovered oils aremore uniform.

Organic peroxides which can be used in this invention include organichydroperoxides, perester compounds and dialkyl peroxides. Examples ofsuitable organic peroxides are as follows: hydroperoxides such ast-butylhydroperoxide, cumenehydroperoxide, p-menthanehydroperoxide andp-cymenehydroperoxide; peresters such as t-butylperoxybenzoate,di-(t-butylperoxy)adipate and t-butylperoxybutyrate; dialkyl peroxidessuch as di-α-cumylperoxide, di-t-butylperoxide and2,5-dimethyl-2',5'-di-(t-butylperoxy)hexane and2,5-dimethyl-2',5'-di-(t-butylperoxy)hexene-3.

A mixture of rubber or plastic wastes to be treated and at least oneorganic peroxide as described above is fed into an extruder and heatedand melted herein. Thereafter the mixture is extruded to a decomposingmeans where the molten mixture is heated at a higher temperature (T₂)than the heating temperature (T₁) in the extruder to prepare decomposedproducts. Afterwards, the decomposed products are heated in adry-distilling means at a lower temperature (T₄) than the heatingtemperature (T₂) in the decomposing means to gasify the decomposedproducts by dry-distillation. As compared with other methods where anorganic peroxide is not added to wastes to be treated, thelast-described process using the organic peroxide is more advantageousin that the decomposition rate is accelerated, the decompositionefficiency is improved and the properties of recovered oils areextremely improved.

If the amount of the residues deposited in the decomposition is large,depending upon the kind of wastes and the kind of additives, aresidue-separating step is preferably added to the above describedsteps. As described hereinbefore, when polyethylene wastes are treatedaccording to the present invention, some wastes include about 3% or soof carbon, and the carbon is in general deposited in the dry-distillingtrough. When the wastes to be treated are crosslinked polyethylene,polystyrene, and ethylene-vinyl acetate copolymer, a metal oxide such asaluminum oxide or silicon oxide is admixed therewith in an appropriateproportion of about 1 to 200 parts per 100 parts by weight of the wastesas hereinbefore described for the purpose of accelerating thedecomposition of wastes and deodorization, and in this case, a largeamount of residues mainly consisting of the metal oxide used aredeposited in the dry-distilling trough. When the residues of carbon ormetal oxides deposited in the dry-distilling trough are removedtherefrom, decomposed products are also removed together with theresidues, causing a deterioration of the decomposition efficiency. Inorder to avoid this defect, a method including this residue-separatingstep is preferred, where heated and molten wastes are heated in adecomposing means at a decomposing temperature (T₂) to separate thedecomposed products from the residues, the residues are heated in aresidue removal means at even higher temperature (T₃) than the heatingtemperature (T₂) in the decomposing means to remove the residues fromthe removal means while the decomposed products are introduced into adry-distilling means, and the decomposed products are heated in thedry-distilling means at a lower temperature (T₄) than the heatingtemperature (T₂) in the decomposing means to gasify them bydry-distillation, and thereafter the thus dry-distilled products arecooled in a cooling means to separate liquid materials from gaseousproducts.

In the method of this invention, the proportion of the organic peroxideto plastic wastes is in general preferably about 0.1 to 20 parts byweight of the organic peroxide to 100 parts by weight of the plasticwastes.

For example, the following combinations are illustrative:

About 1 to 3 parts by weight of di-α-cumylperoxide to 100 parts byweight of low density polyethylene

About 0.5 to 1 part by weight of t-butylhydroperoxide to 100 parts byweight of high density polyethylene

About 0.1 to 0.5 part by weight of t-butylperoxybenzoate to 100 parts byweight of ethylene-vinyl acetate copolymer

About 10 to 20 parts by weight of di-t-butylperoxide to 100 parts byweight of ethylene-propylene rubber

The proportion of organic peroxide to the rubber and plastic wastes isvaried depending upon the kind of rubber and plastic compositions.

It is also effective in the method of this invention to add at least onewhite inorganic filler to wastes treated to increase the decompositionrate and the decomposition efficiency and to improve the uniformity ofthe properties of the recovered oils, which is still a furtherembodiment of this invention.

Examples of white inorganic fillers which can be used in this inventionare talc (magnesium silicate, MgO.SiO₂), clay (aluminum silicate, Al₂O₃.2SiO₂), dolomite (magnesium calcium carbonate), diatomaceous earth(silicic acid hydrate, SiO₂) and alumina (Al₂ O₃).

When plastic wastes containing various kinds of halogen compounds suchas polyvinyl chloride and chlorinated polyethylene are treated, or whenfire retardant polyethylene resins containing halogen-containingcompounds are to be treated, basic metal salts and metal hydroxides arepreferred as the white inorganic filler. In conventional methods fortreatment of plastic wastes containing halogens, the halogen componentscontained in the decomposed gaseous products are introduced into a towerto recover the halogen components as hydrochloric acid, etc., orintroduced into a neutralizing tower to neutralize them with an alkaliin order to prevent environmental pollution. However, these conventionalmethods are defective in that the apparatus must be large-scaled,expenses for initial equipment are high, and the treatment of recoveredproducts such as hydrochloric acid is not easy.

However, when basic metal salts or metal hydroxides are used as a whiteinorganic filler in the method of this invention, the hydrogen halidessuch as HCl generated are solidified as metal halides such as calciumchloride or magnesium chloride. Accordingly, the above describedcomplicated steps in the conventional methods can be markedly reduced oromitted. Examples of basic metal salts and metal hydroxides which can beused in this invention are calcium carbonate, calcium hydroxide, calciumsulfate, magnesium carbonate, magnesium hydroxide, magnesium sulfate,zinc sulfate, sodium carbonate and aluminum hydroxide.

Plastic wastes containing the above described white inorganic filler(s)are fed in an extruder and heated and melted therein, and then themolten wastes are extruded into a decomposing means where they areheated at a higher temperature than the heating temperature in theextruder to form the decomposed products. Thereafter the decomposedproducts are heated in a dry-distilling means at a lower temperaturethan the heating temperature in the decomposing means to gasify theproducts by dry-distillation. As compared with other methods where nowhite inorganic filler is added to the wastes treated, this method usingthe white inorganic fillers is more advantageous in that thedecomposition rate is accelerated, the decomposition efficiency isimproved and the properties of recovered oils are markedly improved. Inparticular, the decomposed products are deodorized and recovered oilshaving more uniform properties can be obtained.

If the amount of residues deposited in the decomposition is large,depending upon the kind of wastes and the kind of additive, it ispreferred to add a residue-separating step to the above described stepsas described hereinbefore.

In the method of this invention, the proportion of white inorganicfiller added to plastic wastes is in general about 1 to 200 parts byweight of white inorganic filler to 100 parts by weight of the plasticwastes. In particular, the proportion of basic metal salt or metalhydroxide to halogencontaining plastics is preferably about 5 to 200parts by weight of the filler to 100 parts by weight of the plasticwastes.

For example, the following combinations are illustrative:

About 5 to 10 parts by weight of talc (magnesium silicate) as a whiteinorganic filler to 100 parts by weight of low density polyethylene

About 1 to 5 parts by weight of clay (aluminum silicate) to 100 parts byweight of high density polyethylene

About 50 parts by weight of diatomaceous earth to 100 parts by weight ofethylene-vinyl acetate copolymer

About 100 to 200 parts by weight of alumina to 100 parts by weight ofethylene-propylene rubber

Suitable proportions of combinations of halogen-containing plastics andwhite inorganic fillers are as follows:

About 50 to 100 parts by weight of calcium carbonate or about 100 to 200parts by weight of calcium hydroxide to 100 parts by weight of polyvinylchloride

About 5 to 10 parts by weight of calcium carbonate to 100 parts byweight of vinyl chloride-vinyl acetate copolymer

The proportion of the white inorganic filler to the rubber and plasticwastes is varied, depending upon the kind of the rubber and plasticwastes. Most rubber and plastic compositions already contain whiteinorganic fillers, and it is preferred to previously analyze thesewastes in an appropriate manner whereby a more accurate proportion ofthe filler to be added to the wastes can be determined.

The present invention will be explained in greater detail with referenceto the following Examples, Comparative Examples and ReferentialExamples. It is to be noted that this invention is not to be construedin any way as being limited to only the illustrated Examples. Unlessotherwise indicated, all parts and percents are by weight.

COMPARATIVE EXAMPLE 1

A low density polyethylene was put in a pressure container (capacity: 1liter), and the polyethylene was heated, melted, decomposed anddry-distilled therein at the same time while heating at 400° C. with anexternal heating means. The liqud components in the decomposed productswere removed from one end of the container, and the composition of theproducts were examined. As a result, it was found that the productsconsisted of 30% of a light fraction having a boiling point of 150° C.or below, 30% of a middle fraction having a boiling point of 150° to250° C. and 40% of a heavy fraction having a boiling point of 250° C. orabove, hereinafter "a light fraction," "a middle fraction" and "a heavyfraction", for brevity.

In the same manner, the polyethylene was liquefied at a heatingtemperature of 600° C., and products consisting of 40% of a lightfraction, 30% of a middle fraction and 30% of a heavy fraction wereobtained. All of these fractions had a strong bad ordor.

COMPARATIVE EXAMPLE 2

A low density polyethylene which had been heated and melted at 200° C.was fed in the same pressre container as in Comparative Example 1, anddecomposed and dry-distilled therein at the same time while heating at400° C. which an external heating means. The liquid components in thedecomposed products were removed from one end of the container and thecomposition of the products was examined. The products consisted of 30%of a light fraction, 30% of a middle fraction and 40% of a heavyfraction. All of these fractions had a strong bad odor.

As shown in the above Comparative Examples 1 and 2, the recovered liquidcomponents obtained according to conventional methods consist ofcompositions over broad range of from a light fraction having a fairlylow flash point to waxes having a high pour point, and recovered oilshaving such a broad composition are unsuitable for practical use havinga poor additional value. For example, a combustion test was carried outwith respect to each of the obtained light fraction, middle fraction andheavy fraction, and the results were as follows. When the light fractionhaving a low flash point was used with an ordinary burner, some problemsoccurred. The middle fraction corresponding to kerosone and light oilcan be used with an ordinary burner. The heavy fraction being waxy andhaving a high pour point is difficult to use at an ordinary temperature.

EXAMPLE 1

Using an apparatus as shown in FIG. 1 where the extruder was a singlespindle screw-type extruder (diameter: 50 mmφ), the length of thedecomposing duct was 1 m and the capacity of the dry-distilling troughwas 1 m³, a low density polyethylene was continuously extruded,pyrolyzed and liquefied according to the method of this invention.

The temperature in the extruder was set as follows:

    ______________________________________                                        Hopper (raw material inlet):                                                                          50° C.                                         First Cylinder:         150° C.                                        Second Cylinder:        250° C.                                        Third Cylinder:         350° C.                                        ______________________________________                                    

The polyethylene was fed in an amount of 100 g/min. The temperature inthe decomposing duct and the temperature in the dry-distilling troughwere set as shown in the following Table 1. Under these conditions, thepolyethylene was pyrolyzed and liquefied according to the method of thisinvention. The composition of the liquid component obtained is shown inTable 1 also.

                                      Table 1                                     __________________________________________________________________________                           Liquid                                                        Temperature                                                                           Temperature                                                                           Component Composition                                         in Decomposing                                                                        in Dry-distilling                                                                     Light                                                                              Middle                                                                             Heavy                                               Duct    Trough  Fraction                                                                           Fraction                                                                           Fraction                                     Run No.                                                                              (° C.)                                                                         (° C.)                                                                         (%)  (%)  (%)                                          __________________________________________________________________________    Comparative                                                                          300-350 300-350 10   20   70                                           Example 3                                                                     Comparative                                                                          400-450 400-450 30   40   30                                           Example 4                                                                     Comparative                                                                          300-350 400-450 20   30   40                                           Example 5                                                                     Comparative                                                                          300-350 450-500 35   35   30                                           Example 6                                                                     Example 1-1                                                                          400-450 300-350 10   70   20                                           Example 1-2                                                                          550-600 300-350 10   80   10                                           Example 1-3                                                                          550-600 250-300 10   85   5                                            Example 1-4                                                                          800-900 250-300 15   80   5                                            __________________________________________________________________________

In Comparative Example 3 above, temperatures in the extruder,decomposing duct and dry-distilling trough all were substantially thesame, and the liquid component obtained mainly consisted of a waxyfraction. It is noticed that the decomposition was not complete.

In Comparative Example 4, the temperatures in the decomposing duct anddry-distilling trough were the same, and the liquid component obtainedbroadly consisted of a light fraction, a middle fraction and a heavyfraction.

In Comparative Examples 5 and 6, the temperature of the dry-distillingtrough was higher than the temperature in the the decomposing duct, andthe results were similar to those of Comparative Example 4.

In Examples 1--1, 1-2, 1-3 and 1-4, decomposed oils mainly consisting ofa middle fraction were obtained.

EXAMPLE 2

Using the same apparatus as described in Example 1, various kinds ofresins were continuously extruded, pyrolyzed and liquefied according tothe method of this invention. The results obtained are shown in thefollowing Table 2.

                                      Table 2                                     __________________________________________________________________________                                         Composition                                                    Temperature                                                                          Temperature in                                                                        of Liquid Component                                Temperature in Decompo-                                                                          Dry-distilling                                                                        Light                                                                              Middle                                                                             Heavy                          Run       in Extruder (° C.)                                                                 sing Duct                                                                            Trough  Fraction                                                                           Fraction                                                                           Fraction                       No.                                                                              Resin Type                                                                           H  C-1                                                                              C-2                                                                              C-3                                                                              (° C.)                                                                        (° C.)                                                                         (%)  (%)  (%)                            __________________________________________________________________________    2-1                                                                              High Density                                                                         50 150                                                                              250                                                                              350                                                                              550-600                                                                              300-350 10   85    5                                Polyethylene                                                               2-2                                                                              Polypropylene                                                                        50 150                                                                              250                                                                              350                                                                              550-600                                                                              300-350 10   80   10                             2-3                                                                              Crosslinked                                                                          50 200                                                                              300                                                                              350                                                                              750-800                                                                              350-400 15   80    5                                Polyethylene                                                               2-4                                                                              Polystyrene                                                                          50 150                                                                              200                                                                              250                                                                              550-600                                                                              300-350 20   70   10                             2-5                                                                              Polyvinyl                                                                            *  120                                                                              150                                                                              200                                                                              550-600                                                                              200-250 30   60   10                                Chloride                                                                   2-6                                                                              Polymethyl-                                                                          100                                                                              200                                                                              300                                                                              350                                                                              500-550                                                                              300-350 20   60   20                                acrylate                                                                   2-7                                                                              Nylon-6                                                                              100                                                                              200                                                                              300                                                                              350                                                                              550-600                                                                              300-350 20   60   20                             2-8                                                                              Ethylene-                                                                            50 200                                                                              300                                                                              350                                                                              550-600                                                                              300-350 20   70   10                                Propylene                                                                     Rubber                                                                     2-9                                                                              Styrene-                                                                             50 200                                                                              300                                                                              350                                                                              500-550                                                                              300-350 20   60   20                                Butadiene                                                                     Rubber                                                                     __________________________________________________________________________     Remarks:                                                                      *: Ordinary temperature                                                       Feeding rate of raw materials: 100 g/min                                      Rotating rate of extruder: 40 rpm                                             H: Temperature in hopper                                                      C-1: Temperature in first cylinder                                            C-2: Temperature in second cylinder                                           C-3: Temperature in third cylinder                                       

The resins used (shown in Table 2 above) were resin compositions.

From the results in Table 2, it can be understood that liquid componentsmainly consisting of a middle fraction are obtained from every resinaccording to the method of this invention. Each resin used in theseexamples is one taken from their respective wastes, and for some resinsresidues separated in the decomposition.

EXAMPLE 3

Using the same apparatus as described in Example 1, a plastic mixture of60% of polyethylene, 25% of polyvinyl chloride, 12% of polystyrene and3% of polypropylene, each resin being a resin composition, wascontinuously extruded, pyrolyzed and liquefied under the same conditionsas in Example 2-3, and liquid components of 60% of a middle fraction,30% of light fraction and 10% of a heavy fraction were obtained.

EXAMPLE 4

Using an apparatus as shown in FIG. 1 where the extruder was a doublespindle screw-type extruder (diameter: 115 mmφ), the length of thedecomposing duct was 1.5 m and the capacity of the dry-distilling troughwas 1 m³, a crosslinked polyethylene was pyrolyzed and liquefiedaccording to the method of this invention. The crosslinked polyethyleneused as a raw material was one removed from a 22 KV crosslinkedpolyethylene cable and pulverized to a size of about 5-10 mm. The rawmaterial was fed to the extruder at a rate of 200 g/min. The rotatingrate of the extruder was set so as to correspond to the feeding speed.

The temperature in the extruder was set as follows:

    ______________________________________                                        Hopper:                50° C.                                          First Cylinder:        200° C.                                         Second Cylinder:       300° C.                                         Third Cylinder:        350° C.                                         ______________________________________                                    

The temperature in the decomposing duct was 700°-750° C. and thetemperature in the dry-distilling trough was 350°-400° C. After thetreatment, the crosslinked polyethylene was observed to be fullypyrolyzed and liquefied. Liquid components obtained consisted of 10% ofa light fraction, 80% of a middle fraction and 10% of a heavy fraction.

EXAMPLE 5

Using an apparatus as shown in FIG. 1 where the extruder was a singlespindle two-stage screw-type extruder (first-stage screw: 115 mmφ,second-stage screw: 90 mmφ), having a length of the decomposing duct of2 m and a capacity of the dry-distilling trough of 1 m³, a crosslinkedpolyethylene was pyrolyzed and liquefied according to the method of thisinvention. The crosslinked polyethylene used as the raw material was thesame as for the sample as in Example 3. The temperature in the extruderwas set as follows:

    ______________________________________                                        First-stage Screw Hopper:  50° C.                                      First-stage Screw Cylinder:                                                                              200° C.                                     First Cylinder of Second-stage Screw:                                                                    300° C.                                     Second Cylinder of Second-stage Screw:                                                                   350° C.                                     ______________________________________                                    

The temperature in the decomposing duct was 650°-700° C. and thetemperature in the dry-distilling trough was 300°-350° C. The liquidcomponents obtained consisted of 10% of a light fraction, 85% of amiddle fraction and 5% of a heavy fraction.

As is apparent from the results in the above Examples, when rubber andplastic wastes are continuously extruded, pyrolyzed and liquefiedaccording to the method of this invention, recovered oils having uniformproperty (or mainly consisting of a middle fraction) can be obtained.

The apparatus of this invention is small in size and extremely compact,as compared with conventional pyrolyzing and liquefying apparatus, whichis one advantage of this invention.

EXAMPLE 6

Using an apparatus as shown in FIG. 1 where the extruder is a singlespindle screw-type extruder (diameter: 50 mmφ), the length of thedecomposing duct was 1 m and the capacity of the dry-distilling troughwas 1 m³, a low density polyethylene was continuously extruded,pyrolyzed and liquefied according to the method of this invention.

The temperature in the extruder was set as follows:

    ______________________________________                                        Hopper (raw material inlet):                                                                          50° C.                                         First Cylinder:         150° C.                                        Second Cylinder:        250° C.                                        Third Cylinder:         350° C.                                        ______________________________________                                    

The feeding rate of the polyethylene raw material was 100 g/min. Thekind and the feeding rate of active gas are shown in the following Table3. The temperature in the decomposing duct and that in thedry-distilling trough are also shown in Table 3. Under these conditions,the polyethylene was pyrolyzed and liquefied according to the method ofthis invention. The liquid components obtained were examined and thecomposition thereof is also shown in Table 3.

Run No. 1 mainly consisted of a waxy heavy fraction, with a somewhat badodor. This is because the decomposition of the raw material was notcompleted.

Run No. 2 which was treated under the same heating conditions as for RunNo. 1 with the exception that oxygen gas was introduced duringdecomposition, mainly consisted of a middle fraction, being free from abad odor. Comparing Run No. 3 with Run No. 4, Run No. 5 with Run No. 6,and Run No. 7 with Run No. 8, it is observed that when the active gaswas introduced during the decomposition, liquid components without a badodor and having a more uniform property could be obtained, whereas whenan active gas was not introduced, the liquid components obtained had asomewhat bad odor.

                                      Table 3                                     __________________________________________________________________________    Temperature         Temperature                                                                           Composition of Liquid                             in          Active  in      Component                                              Decomposing                                                                          Gas     Dry-distilling                                                                        Light                                                                              Middle                                                                             Heavy                                        Duct   and     Trough  Fraction                                                                           Fraction                                                                           Fraction                                                                           Presence                           Run No.                                                                            (° C.)                                                                        Feeding Rate                                                                          (° C.)                                                                         (%)  (%)  (%)  of Bad Odor                        __________________________________________________________________________    1    300-350                                                                              None    300-350 10   20   70   Somewhat observed                  2    300-350                                                                              Oxygen gas,                                                                           300-350 10   60   30   Not observed                                   10 liter/min                                                                  at 1 atm                                                          3    400-450                                                                              None    400-450 30   40   30   Somewhat observed                  4    400-450                                                                              Ozone gas                                                                             400-450 10   80   10   Not observed                                   5 liter/min                                                                   at 1 atm                                                          5    550-600                                                                              None    300-350 10   60   30   Somewhat observed                  6    550-600                                                                              Air     250-300 10   85    5   Not observed                                   15 liter/min at                                                               1 atm                                                             7    800-900                                                                              None    300-350 10   80   10   Somewhat observed                  8    800-900                                                                              Hydrogen gas                                                                          250-300 15   80    5   Not observed                                   10 liter/min                                                                  at 1 atm                                                          __________________________________________________________________________

EXAMPLE 7

Using the same apparatus as described in Example 6, various kinds ofresins were continuously extruded, pyrolyzed and liquefied according tothe method of this invention. The results obtained are shown in thefollowing Table 4. The feeding rate of the respective raw material was100 g/min. In this Table 4, H is the temperature in the hopper of theextruder, C-1 is the temperature in the first cylinder of the extruder,C-2 is the temperature in the second cylinder of the extruder, and C-3is the temperature in the third cylinder of the extruder.

It is observed from the results in Table 4 that liquid components mainlyconsisting of a large amount of a middle fraction and being free frombad odor could be obtained from every resin. The resin used in Table 4was a resin composition which was taken from the respective wastes.Separated residues were obtained from some of the resins duringdecomposition.

                                      Table 4                                     __________________________________________________________________________                                       Tempera-                                                          Tempera-    ture in                                                                            Composition                                                  ture in                                                                              Active                                                                             Dry-dis-                                                                           of Liquid         Presence                       Temperature Decomposing                                                                          Gas and                                                                            tilling                                                                            Component (%)     of                  Run        in Extruder (° C.)                                                                 Duct   Feeding                                                                            Trough                                                                             Light Middle                                                                              Heavy bad                 No.                                                                              Resin Type                                                                            H  C-1                                                                              C-2                                                                              C-3                                                                              (° C.)                                                                        Rate (° C.)                                                                      Fraction                                                                            Fraction                                                                            Fraction                                                                            odor                __________________________________________________________________________    1  High Density                                                                          50 150                                                                              250                                                                              350                                                                              550-600                                                                              Oxygen                                                                             300-350                                                                            10    90     0    None                   Polyethylene               10 l/min                                        2  Polypropylene                                                                         50 150                                                                              250                                                                              350                                                                              550-600                                                                              Oxygen                                                                             300-350                                                                            10    85     5    None                                              10 l/min                                        3  Crosslinked                                                                           50 200                                                                              300                                                                              350                                                                              750-800                                                                              Oxygen                                                                             350-400                                                                             5    90     5    None                   Polyethylene               10 l/min                                        4  Polystyrene                                                                           50 150                                                                              200                                                                              250                                                                              550-600                                                                              Ozone                                                                              300-350                                                                            10    80    10    None                                              7 l/min                                         5  Polyvinyl                                                                             *  120                                                                              150                                                                              200                                                                              550-600                                                                              Air  200-250                                                                            20    70    10    None                   Chloride                   15 l/min                                        6  Polymethyl                                                                            100                                                                              200                                                                              300                                                                              350                                                                              550-600                                                                              Oxygen                                                                             300-350                                                                            10    85     5    None                   Acrylate                   10 l/min                                        7  Nylon-6 100                                                                              200                                                                              300                                                                              350                                                                              550-600                                                                              Oxygen                                                                             300-350                                                                            15    75    10    None                                              10 l/min                                        8  Ethylene                                                                              50 200                                                                              300                                                                              350                                                                              550-600                                                                              Oxygen                                                                             300-350                                                                            10    80    10    None                   Propylene                  10 l/min                                           Rubber                                                                     9  Styrene 50 200                                                                              300                                                                              350                                                                              550-600                                                                              Oxygen                                                                             300-350                                                                            10    80    10    None                   Butadiene                  10 l/min                                           Rubber                                                                     __________________________________________________________________________     Remarks:                                                                      *: Ordinary temperature                                                  

EXAMPLE 8

Using the same apparatus as described in Example 6, a plastic mixtureconsisting of resin compositions of 60% of polyethylene, 25% ofpolyvinyl chloride, 12% of polystyrene and 3% of polypropylene wascontinuously extruded, pyrolyzed and liquefied under the same conditionsas in Example 7-3. The liquid component obtained consisted of 60% of amiddle fraction, 30% of a light fraction and 10% of a heavy fraction,and this component was quite free from any bad odor.

EXAMPLE 9

Using an apparatus shown in FIG. 2 where the extruder was a doublespindle screw-type extruder (diameter: 115 mmφ), the length of thedecomposing duct was 1.5 m and a capacity of the dry-distilling troughwas 1 m³, a crosslinked polyethylene was pyrolyzed and liquefiedaccording to the method of this invention. The crosslinked polyethyleneused as a raw material was one removed from a 22 KV crosslinkedpolyethylene cable and pulverized to a size of about 5-10 mm. The rawmaterial was fed into the extruder at a rate of 200 g/min. The rotatingrate of the extruder was set so as to correspond to the feeding rate.The temperature in the extruder was set as follows:

    ______________________________________                                        Hopper:                50° C.                                          First Cylinder:        200° C.                                         Second Cylinder:       300° C.                                         Third Cylinder:        350° C.                                         ______________________________________                                    

The temperature in the decomposing duct was 700°-750° C. and thetemperature in the dry-distilling trough was 350°-400° C. Oxygen wasintroduced through the active gas inlet. After treatment, thecrosslinked polyethylene was observed to be fully pyrolyzed andliquefied. The liquid components obtained consisted of 10% of a lightfraction, 85% of a middle fraction and 10% of a heavy fraction. Eachfraction was free from any bad odor.

EXAMPLE 10

Using an apparatus as shown in FIG. 2 where the extruder was a singlespindle two-stage screw-type extruder (first-stage screw: 115 mmφ,second-stage screw: 90 mmφ), the length of the decomposing duct was 2 mand the capacity of the drydistilling trough was 1 m³, a crosslinkedpolyethylene was pyrolyzed and liquefied according to the method of thisinvention. The crosslinked polyethylene used was the same kind of sampleas described in Example 9. The temperature in the extruder was set asfollows:

    ______________________________________                                        First-stage Screw Hopper:  50° C.                                      First-stage Screw Cylinder:                                                                              200° C.                                     First Cylinder of Second-stage Screw:                                                                    300° C.                                     Second Cylinder of Second-stage Screw:                                                                   350° C.                                     ______________________________________                                    

The temperature in the decomposing duct was 650°-700° C. and thetemperature in the dry-distilling trough was 300°-350° C. Under theseconditions, the polyethylene raw material was pyrolyzed and liquefiedaccording to the method of this invention. The feeding rate of the rawmaterial was 250 g/min. Oxygen gas was fed through the active gas inletat a feeding rate of 15 liter/min. The liquid components obtainedconsisted of 5% of a light fraction, 90% of a middle fraction and 5% ofa heavy fraction. All fractions were free from any bad odor.

COMPARATIVE EXAMPLE 3

Using an apparatus as shown in FIG. 1 where the extruder was a singlespindle screw-type extruder (diameter: 50 mmφ), the length of thedecomposing duct was 1 m and the capacity of the dry-distilling troughwas 1 m³, a plastic mixture of resin compositions of 30% ofpolyethylene, 25% of polyvinyl chloride, 25% of polystyrene and 20% ofpolypropylene was continuously extruded, pyrolyzed and liquefied.

The temperature in the extruder was set as follows:

    ______________________________________                                        Hopper (raw material inlet):                                                                          50° C.                                         First Cylinder:         150° C.                                        Second Cylinder:        250° C.                                        Third Cylinder:         350° C.                                        ______________________________________                                    

The feeding rate of the plastic mixture was 100 g/min. The temperaturein the decomposing duct was 550°-600° C. and the temperature in thedry-distilling trough was 400°-450° C. After treatment, liquidcomponents consisting of 30% of a light fraction, 50% of a middlefraction and 20% of a heavy fraction were obtained.

EXAMPLE 11

Using an apparatus as shown in FIGS. 1 and 4 where the first extruderwas a double spindle screw-type extruder (diameter: 115 mmφ), the lengthof the decomposing duct connected therewith was 1.5 m, the secondextruder was a single spindle screw-type extruder (diameter: 115 mmφ),the length of the decomposing duct connected therewith was 1.5 m, andthe capacity of the dry-distilling trough was 2 m³, a crosslinkedpolyethylene was fed into the first extruder and a low densitypolyethylene was fed into the second extruder, and these raw materialswere continuously pyrolyzed and liquefied. The crosslinked polyethyleneand low density polyethylene used as raw materials were materialsremoved from 22 KV insulated cables and pulverized to a size of about5-10 mm. The feeding rate of each of these raw materials into therespective extruders was 100 g/min, and the rotating rate of therespective extruders was set so as to correspond to the respectivefeeding rates of the raw materials. The temperatures in the extruders,decomposing ducts and dry-distilling trough were as follows:

    ______________________________________                                        First Extruder:     H:        50° C.                                                       C-1:     200° C.                                                       C-2:     300° C.                                                       C-3:     350° C.                                   First Decomposing Duct:      750°-800° C.                       Second Extruder:    H:        50° C.                                                       C-1:     150° C.                                                       C-2:     250° C.                                                       C-3:     350° C.                                   Second Decomposing Duct:     550°-600° C.                       Dry-distilling Trough:       350°-400° C.                       ______________________________________                                    

The liquid components obtained consisted of 15% of a light fraction, 80%of a middle fraction and 5% of a heavy fraction.

COMPARATIVE EXAMPLE 4

The low density polyethylene and the crosslinked polyethylene asdescribed in the Example 11 were blended in a weight proportion of 1:1,and the mixture was fed into the first extruder as described in Example11 and continuously pyrolyzed and liquefied. The liquid componentsobtained consisted of 40% of a light fraction 50% of a middle fractionand 10% of a heavy fraction. In the same manner, the mixture was fedinto the second extruder and continuously pyrolyzed and decomposed. Theliquid components obtained consisted of 20% of a light fraction, 50% ofa middle fraction and 30% of a heavy fraction.

EXAMPLE 12

Using an apparatus as shown in FIGS. 1 and 5, where the first extruderwas a single spindle two-stage screw-type extruder (first-stage screw:115 mmφ, second-stage screw: 90 mmφ), the length of the decomposing ductconnected therewith was 2 m, the second extruder was a single spindlescrew-type extruder (90 mmφ), the length of the decomposing ductconnected therewith was 2 m, the third extruder was a double spindlescrew-type extruder (115 mmφ), the length of the decomposing ductconnected therewith was 2 m, and the capacity of the dry-distillingtrough was 3 m³, a polyvinyl chloride resin composition was fed into thefirst extruder, a polystyrene resin composition into the second extruderand a high density polyethylene into the third extruder, and these rawmaterials were continuously pyrolyzed and liquefied according to themethod of this invention. Each of these raw materials was a materialremoved from their respective wastes. The feeding rate of each rawmaterial was 100 g/min, and the rotating rate of each extruder was setso as to correspond to the feeding rate. The temperatures in therespective extruders, decomposing ducts and dry-distilling trough wereas follows:

    ______________________________________                                        First Extruder:                                                                            First-stage Screw:                                                                          H:      50° C.                                                         C-1:    50° C.                                                         C-2:   200° C.                                           Second-stage Screw:                                                                         C-1:   250° C.                                                         C-2:   250° C.                              First Decomposing                 450°-500° C.                  Duct:                                                                         Second Extruder:           H:      50° C.                                                         C-1:   150° C.                                                         C-2:   200° C.                                                         C-3:   250° C.                              Second Decomposing                550°-600° C.                  Duct:                                                                         Third Extruder             H:      50° C.                                                         C-1:   150° C.                                                         C-2:   250° C.                                                         C-3:   350° C.                              Third Decomposing                 600°-650° C.                  Duct:                                                                         Dry-distilling                    350°-650° C.                  Trough:                                                                       ______________________________________                                    

The liquid components obtained consisted of 20% of a light fraction, 75%of a middle fraction and 5% of a heavy fraction.

COMPARATIVE EXAMPLE 5

A polyvinyl chloride resin, a polystyrene and a high densitypolyethylene as described in Example 12 were blended in a weightproportion of 1:1:1, and the mixture was fed into the first extruder ofan apparatus as described in Example 12 and continuously pyrolyzed andliquefied. The liquid components obtained consisted of 30% of a lightfraction, 30% of a middle fraction and 40% of a heavy fraction.

In the same manner, the mixture was fed into the second extruder of anapparatus as described in Example 12 and continuously pyrolyzed andliquefied. The liquid components obtained consisted of 30% of a lightfraction, 40% of a middle fraction and 30% of a heavy fraction.

Also in the same manner, the mixture was fed into the third extruder ofan apparatus as described in Example 12 and continuously pyrolyzed andliquefied. The liquid components obtained consisted of 30% of a lightfraction, 50% of a middle fraction and 20% of a heavy fraction.

EXAMPLE 13

Using an apparatus as shown in FIGS. 1 and 6 where the first extruderwas a single spindle two-stage screw type extruder (first-stage screw:115 mmφ, second-stage screw: 90 mmφ), the length of the decomposing ductconnected therewith was 2 m, the second extruder was a single spindlescrew-type extruder (90 mmφ), the length of the decomposing ductconnected therewith was 2 m, the third extruder was a double spindlescrew-type extruder (115 mmφ), the length of the decomposing ductconnected therewith was 2 m, the fourth extruder was a single spindlescrew-type extruder (115 mmφ), the length of the decomposing ductconnected therewith was 2 m, and the capacity of the dry-distillingtrough was 3 m³, a polyvinyl chloride resin was fed into the firstextruder, an ethylene-propylene rubber composition into the secondextruder, a crosslinked polyethylene composition into the third extruderand a polypropylene resin into the fourth extruder and these resins werecontinuously pyrolyzed and liquefied according to the method of thisinvention. The respective raw materials used were each taken from theirrespective wastes. The feeding rate of the respective resin was 100g/min, and the rotation rate of the respective extruder was set so as tocorrespond to the respective feeding rate.

The temperatures in the respective extruders, decomposing ducts anddry-distilling trough were as follows:

    ______________________________________                                        First Extruder:                                                                            First-stage Screw:                                                                          H:      50° C.                                                         C-1:   150° C.                                                         C-2:   200° C.                                           Second-stage Screw:                                                                         C-1:   250° C.                                                         C-3:   250° C.                              First Decomposing                 450°-500° C.                  Duct:                                                                         Second Extruder:           H:      50° C.                                                         C-1:   200° C.                                                         C-2:   300° C.                                                         C-3:   350° C.                              Second Decomposing                550°-600° C.                  Duct:                                                                         Third Extruder:            H:      50° C.                                                         C-1:   200° C.                                                         C-2:   300° C.                                                         C-3:   350° C.                              Third Decomposing                 700°-750° C.                  Duct:                                                                         Fourth Extruder:           H:      50° C.                                                         C-1:   150° C.                                                         C-2:   250° C.                                                         C-3:   350° C.                              Fourth Decomposing                550°-600° C.                  Duct:                                                                         Dry-distilling                    350°-400° C.                  Trough:                                                                       ______________________________________                                    

The liquid components obtained consisted of 15% of a light fraction, 80%of a middle fraction and 5% of a heavy fraction.

EXAMPLE 14

Using an apparatus as shown in FIG. 1, where the extruder was a singlespindle screw-type extruder (50 mmφ), the length of the decomposing ductwas 1 m and the capacity of the dry-distilling trough was 1 m³, a lowdensity polyethylene to which was added an organic peroxide wascontinuously extruded, pyrolyzed and liquefied according to the methodof this invention.

The temperature in the extruder was set as follows:

    ______________________________________                                        Hopper (raw material inlet):                                                                          50° C.                                         First Cylinder:         150° C.                                        Second Cylinder:        250° C.                                        Third Cylinder:         350° C.                                        ______________________________________                                    

The feeding rate of the polyethylene raw material was 100 g/min. Thekind and the amount of organic peroxide used are shown in the followingTable 5. The temperature in the decomposing duct and that in thedry-distilling trough are also shown in Table 5 The composition ofliquid components obtained is given in Table 5.

                                      Table 5                                     __________________________________________________________________________                             Composition of                                       Temperature                                                                             Organic                                                                              Temperature in                                                                        Liquid Component (%)                                    in Decompo-                                                                          Peroxide                                                                             Dry-distilling                                                                        Light                                                                              Middle                                                                             Heavy                                      Run                                                                              sing Duct                                                                            and    Trough  Fraction                                                                           Fraction                                                                           Fraction                                                                           Presence of                           No.                                                                              (° C.)                                                                        Amount Used                                                                          (° C.)                                                                         (%)  (%)  (%)  Bad Odor                              __________________________________________________________________________    1  400-450                                                                              None   300-350 10   50   40   Somewhat observed                     2  400-450                                                                              Di-α-cumyl-                                                                    300-350 10   70   20   Not observed                                    peroxide                                                                      5 g/min                                                             3  550-600                                                                              None   300-350 10   60   30   Somewhat observed                     4  550-600                                                                              t-Butylhydro-                                                                        300-350 10   80   10   Not observed                                    peroxide                                                                      1 g/min                                                             5  800-900                                                                              None   300-350 10   80   10   Somewhat observed                     6  800-900                                                                              t-Butylper-                                                                          300-350 10   85    5   Not observed                                    oxybenzoate                                                                   0.5 g/min                                                           __________________________________________________________________________

In Table 5, Run Nos. 2, 4, and 6 contain an organic peroxide, and RunNos. 1, 3 and 5 do not contain any organic peroxide.

Run No. 1 product mainly consisted of a waxy heavy fraction, having asomewhat bad odor. This is because the decomposition of the raw materialwas not complete. Run No. 2 product which was treated under the sameheating conditions as in Run No. 1 with the exception thatdi-α-cumylperoxide was introduced as an organic peroxide during thedecomposition, mainly consisted of a middle fraction, which was freefrom any bad odor. Comparing Run No. 3 with Run No. 4, and Run No. 5with Run No. 6, it is observed that when the organic peroxide wasintroduced during the decomposition, liquid components without a badodor and having more uniform properties could be obtained, whereas whenan organic peroxide was not introduced, the liquid components obtainedhave a somewhat bad odor.

EXAMPLE 15

Using an apparatus as shown in FIG. 1 where the extruder was a singlespindle screw-type extruder (50 mmφ), the length of the decomposing ductwas 1 m and the capacity of the dry-distilling trough was 1 m³, a lowdensity polyethylene containing a white inorganic filler wascontinuously extruded, pyrolyzed and liquefied according to the methodof this invention.

The temperature in the extruder was set as follows:

    ______________________________________                                        Hopper (raw material inlet):                                                                          50° C.                                         First Cylinder:         150° C.                                        Second Cylinder:        250° C.                                        Third Cylinder:         350° C.                                        ______________________________________                                    

The feeding rate of the polyethylene was 100 g/min, and the kind and theamount of white inorganic filler used are shown in the following Table6. The temperature in the decomposing duct and the temperature in thedry-distilling trough are also given in Table 6. The liquid productsobtained were examined and the composition thereof is given in Table 6.

                                      Table 6                                     __________________________________________________________________________    Temperature          Temperature                                                                           Composition of                                   in          White In-                                                                              in      Liquid Component                                      Decomposing                                                                          organic Filler                                                                         Dry-distilling                                                                        Light                                                                              Middle                                                                             Heavy                                       Duct   and      Trough  Fraction                                                                           Fraction                                                                           Fraction                                                                           Presence                          Run No.                                                                            (° C.)                                                                        Amount Used                                                                            (° C.)                                                                         (%)  (%)  (%)  of Bad Odor                       __________________________________________________________________________    1    400-450                                                                              None     300-350 10   50   40   Somewhat observed                 2    400-450                                                                              Talc(magnesium                                                                         300-350 10   60   30   Not observed                                  silicate)                                                                     10g/min                                                           3    550-600                                                                              None     350-400 15   65   20   Somewhat observed                 4    550-600                                                                              Clay(aluminum                                                                          350-400 10   75   15   Not observed                                  silicate)                                                                     20g/min                                                           5    550-600                                                                              Alumina  350-400 10   80   10   Not observed                                  10g/min                                                           6    800-900                                                                              None     350-400 15   75   10   Somewhat observed                 7    800-900                                                                              Dolomite 350-400 10   80   10   Not observed                                  50g/min                                                           8    800-900                                                                              Diatomaceous                                                                           350-400 10   80   10   Not observed                                  earth                                                                         20g/min                                                           __________________________________________________________________________

In Table 6, Run Nos. 2, 4, 5, 7 and 8 contained a white inorganicfiller, and Run Nos. 1, 3 and 6 did not contain a white inorganicfiller.

Run No. 1 product mainly consisted of a waxy heavy fraction, having asomewhat bad odor. This was because the decomposition of the rawmaterial was not complete. Run No. 2 product which was treated under thesame heating conditions as in Run No. 1 with the exception that talc wasincorporated in the raw material as a white inorganic filler, mainlyconsisted of a middle fraction, which was free from any bad odor.

Comparing Run No. 3 with Run Nos. 4 and 5, and Run No. 6 with Run Nos. 7and 8, it is observed that when the white inorganic filler wasincorporated in the raw material, liquid components without a bad odorand having more uniform properties could be obtained, whereas when awhite inorganic filler was not incorporated the liquid componentsobtained had a somewhat bad odor.

EXAMPLE 16

Using the same apparatus as described in Example 15, wastes of vinylchloride film for agricultural use, to which calcium carbonate was addedas a white inorganic filler, were continuously extruded, pyrolyzed andliquefied according to the method of this invention.

The temperature in the extruder was set as follows:

    ______________________________________                                        Hopper (raw material inlet):                                                                       50° C.                                            First Cylinder:      150° C.                                           Second Cylinder:     200° C.                                           Third Cylinder:      250° C.                                           ______________________________________                                    

The feeding rate of the vinyl chloride wastes was 100 g/min, and that ofthe calcium carbonate was 100 g/min. The temperature in the decomposingduct was 500°-550° C. and the temperature in the dry-distilling troughwas 300°-350° C. No hydrogen chloride gas was removed from the gasremoval outlet.

For comparison, the same treatment was carried out with the exceptionthat no calcium carbonate was employed. In the latter case, a largeamount of pungent hydrogen chloride gas was exhausted from the gasremoval outlet.

While the invention has been described in detail and with reference tospecific embodiments thereof, it will be apparent to one skilled in theart that various changes and modifications can be made therein withoutdeparting from the spirit and scope thereof.

What is claimed is:
 1. An apparatus for treatment of rubber and plasticwastes, comprising:(1) an extruder for controlled heating and melting ofrubber and plastic wastes, said extruder kneading the molten wastes andextruding them, means to heat said extruder and control means toregulate said means to heat said extruder; (2) a decomposing meanscoupled to said extruder and receiving the melted rubber and plasticwastes from the extruder, said decomposing means having means forheating in a controlled manner the melted wastes therein to formdecomposed products; (3) a dry-distilling means coupled to saiddecomposing means, said dry-distilling means having controlled heatingmeans for gasifying said decomposed products of the decomposing means bydry-distillation; and (4) a cooling means coupled to said dry-distillingmeans for receiving the dry-distilled products to separate liquidmaterials from gaseous materials wherein the temperature of said coolingmeans is individually controllable.
 2. The apparatus as claimed in claim1, wherein:said decomposing means includes a residue removal means as abranch at an outlet thereof, for removing the residues from thedecomposing means after the decomposed products contained in theresidues have been separated therefrom, in which the temperature of saidresidue removal means is individually controllable.
 3. The apparatus asclaimed in claim 1 including:(1) a plurality of extruders for heatingand melting rubber and plastic wastes, (2) a plurality of decomposingmeans for receiving the melted rubber and plastic wastes and for heatingthe wastes to form decomposed products.
 4. The apparatus as claimed inclaim 1 wherein the decomposing means includes active gas feeding inletmeans.